Video cameras are used for many applications ranging from security systems to various industrial uses such as monitoring and recording manufacturing operations. Many of these applications expose the camera to extreme environmental conditions, such as extreme temperatures, high humidity, corrosive elements and air-borne particles.
To protect the cameras from these conditions, they are typically mounted within an environmentally controlled housing. A common method of controlling the internal temperature of such housings in high temperature environments is to employ a heat sink alone or in combination with a mechanical cooling device, such as a fan or blower. The heat sink is adapted to transfer heat away from an internal chamber of the housing enclosing the camera. In situations where the use of a heat sink alone provides inadequate heat transfer, one or more fans may be mounted adjacent to the heat sink to blow air across the heat sink and thereby increase the rate of heat transfer from the internal chamber.
One drawback of using a fan and/or other cooling devices having moving mechanical parts is that they are susceptible to wear and premature failure in environments having high heat and humidity, air-borne particles, and/or other corrosive elements. The constant exposure of mechanical cooling devices to these types of environmental conditions may, over a relatively short period of time, corrode or clog bearings and other moving parts, requiring these parts to be frequently serviced or replaced.
Another prior art system of cooling the internal chamber of a camera housing assembly employs one or more pumps for pumping a cooling fluid through tubing or other fluid passageways disposed within the housing. One disadvantage of these types of systems is that they may require extensive and complex support equipment for each housing, and are therefore financially impractical, especially for applications that require a number of cameras mounted at various remote locations, such as security systems. In addition, the pumps are susceptible to wear and premature failure in environments having air-borne particulates and/or other corrosive elements.